The work to be undertaken is a series of studies of the chemistry of anterior pituitary growth hormone and prolactin of different species of animals. This involves isolation of purification of growth hormone and prolactin, determination of their physical and chemical characteristics, and studies of the relationship between structure and function as this may be revealed by partial degradation of the molecules by chemical and enzymatic means. The objectives are to determine the structural requirements for activity and to gain a better understanding of the basis of species specificity. The proposed work involves 1) isolation and purification of growth hormone from pituitaries of pigeon, chick, and one (possibly 2) teleost fish; 2) further chemical and physical characterization of canine, porcine and monkey growth hormones; 3) systematic studies of alteration of structure of porcine and bovine GH by progressive deamidation, to investigate the part net charge may play in immunochemical and biological specificity; 4) further work on the isolation of "high-prolactin" fractions of human growth hormone, an order a) to see whether a practical "pseudo-prolactin" low in growth activity can be prepared, which might have experimental or therapeutic utility and b) to try to understand the structural requirements for prolactin activity by hGH; 5) to complete studies on the isolation and characterization of porcine prolactin.